Surgical variable-angle illuminator

ABSTRACT

A variable-angle, wide-angle illuminator is disclosed, one embodiment being a small-gauge, variable-angle illumination surgical system comprising: a light source for providing a light beam; an optical cable, optically coupled to the light source for receiving and transmitting the light beam; a handpiece, operably coupled to the optical cable; an optical fiber, operably coupled to the handpiece, wherein the optical fiber is optically coupled to the optical cable to receive and transmit the light beam; an optical assembly, optically coupled to a distal end of the optical fiber, for receiving the light beam and providing the light beam to illuminate a surgical field; and a cannula, operably coupled to the handpiece and optical assembly, for housing and directing the optical assembly to illuminate selected area. The optical assembly can comprise a fiber/polymer-dispersed-liquid-crystal (“PDLC”) diffuser optically coupled to an optical needle or a nested compound parabolic concentrator (“CPC”) cone.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority under 35 U.S.C. §119 to U.S.Provisional Patent Application No. 60/731,942, filed Oct. 31, 2005, theentire contents of which are incorporated herein by reference.

TECHNICAL FIELD OF THE INVENTION

The present invention relates generally to surgical instrumentation. Inparticular, the present invention relates to surgical instruments forilluminating an area during eye surgery. Even more particularly, thepresent invention relates to a variable-angle, small gauge, wide-angleilluminator for illumination of a surgical field.

BACKGROUND OF THE INVENTION

In ophthalmic surgery, and in particular in vitreo-retinal surgery, itis desirable to use a wide-angle surgical microscope system to view aslarge a portion of the retina as possible. Wide-angle objective lensesfor such microscopic systems exist, but they require a widerillumination field than that provided by the cone of illumination of atypical fiber-optic probe. As a result, various technologies have beendeveloped to increase the beam spreading of the relatively incoherentlight provided by a fiber-optic illuminator. These known wide-angleilluminators can thus illuminate a larger portion of the retina asrequired by current wide-angle surgical microscope systems. Currentlyexisting wide-angle illuminators, however, display severaldisadvantages.

One disadvantage exhibited by some prior art wide-angle illuminators forophthalmic surgery is matching of the light refracting index of thevitreous eye fluid to that of the light refracting surface of the lensof the illuminator that comes in contact with the vitreous eye fluid.Contact of the vitreous eye fluid with the light refracting surface ofthe light spreading lens of such prior art systems results insub-optimal light refraction due to index switching caused by thevitreous eye fluid. U.S. Pat. No. 5,624,438, entitled “RetinalWide-Angle Illuminator For Eye Surgery,” and issued to R. Scott Turner,provides a system for overcoming the effect of refractive index matchingthrough the use of a high refractive-index step, mediated by thepresence of an air-gap. The air-gap is presented between the distal endof an optical fiber and the light refracting surface of the illuminatorlens. The light emanating from the optical wave guide (i.e., the opticalfiber) will therefore undergo angular dispersion without any indexswitching that might be caused by contact with the vitreous eye fluidbefore it passes through the light refracting surface of the illuminatorlens.

Another disadvantage of currently available wide-angle illuminators isglare. Glare results when the source of the illumination is small andbright, and the user (e.g., an ophthalmic surgeon) has a direct line ofsight to the small bright illumination source. Glare is unwanted strayradiation that provides no useful illumination, and either distracts anobserver or obscures an object under observation. Glare can be correctedfor in current wide-angle illuminators, but typically only by reducingthe total illumination light flux, which reduces the amount of lightavailable for observation by the surgeon. For example, the “bulletprobe” manufactured by Alcon Laboratories, Inc., of Fort Worth, Tex.,achieves wide-angle illumination by using a bullet-shaped fiber having asurface diffusive finish to scatter light emanating from the distal endof an optical fiber. To reduce glare, the bullet probe can use ageometric shield, which reduces the illumination angle by reducing theoverall available light flux.

A further disadvantage of prior art wide-angle illuminators is that theydo not provide for varying the illumination angle (angular spread) ofthe light source to adjust illumination for different conditions withinthe surgical field in real time.

Therefore, a need exists for a variable-angle, wide-angle illuminatorthat can reduce or eliminate the problems of associated with prior artwide-angle illuminators, particularly the problem of varying the angularspread of the emitted light in real time.

BRIEF SUMMARY OF THE INVENTION

The embodiments of the variable-angle, wide-angle surgical illuminatorof the present invention substantially meet these needs and others. Oneembodiment of this invention is a small-gauge, variable-angleillumination surgical system comprising: a light source for providing alight beam; an optical cable, optically coupled to the light source forreceiving and transmitting the light beam; a handpiece, operably coupledto the optical cable; an optical fiber, operably coupled to thehandpiece, wherein the optical fiber is optically coupled to the opticalcable to receive and transmit the light beam; an optical assembly,optically coupled to a distal end of the optical fiber, for receivingthe light beam and providing the light beam to illuminate an area; and acannula, operably coupled to the handpiece and optical assembly, forhousing and directing the optical assembly.

The optical assembly can comprise afiber/polymer-dispersed-liquid-crystal (“PDLC”) diffuser/glass needle ora nested compound parabolic concentrator (“CPC”) cone. In the PDLCdiffuser/glass needle embodiment, the fiber can be a standardendo-illuminator optical fiber with 0.50 NA or similar value. The lightbeam from the light source is transmitted by the optical fiber andprovided to a PDLC diffuser for further transmission and diffusion ofthe light beam. The degree of diffusion of the light beam at the PDLCdiffuser can be electrically controlled and can be varied from nodiffusion to a very high degree of diffusion. After passing through thePDLC diffuser, the light beam is provided to an optical needle or fiber(e.g., glass) that transmits the light beam to illuminate a desiredarea, such as a surgical site in the eye.

In the CPC cone embodiment, the distal end of the optical fiber isterminated in a CPC-cone shape that angularly spreads the light out to ahigh off-axis angle and emits the light out of the distal end of thecannula with high efficiency. Almost all of the light beam escapes theoptical fiber and CPC-cone through the planar distal end face. A maleCPC-cone is separated from a truncated female CPC-cone by a small airgap. When the male and female CPC-cones are pulled together to makeoptical contact, the light from the male CPC-cone element is freelytransmitted into the female CPC-cone element, and the resultant light isemitted over a greatly reduced angular spread.

The cannula, optical assembly and the handpiece can be fabricated frombiocompatible materials. The optical cable can comprise a first opticalconnector operably coupled to the light source and a second opticalconnector operably coupled to the handpiece (to optically couple theoptical cable to the optical fiber housed within the handpiece andcannula). These connectors can be SMA optical fiber connectors. Theoptical assembly, optical fiber and optical cable (i.e., the opticalfibers within the optical cable) can be of a compatible gauge so as totransmit the light beam from the light source to the surgical field. Forexample, all three elements could be of equal gauge.

Other embodiments of the present invention can include a method forwide-angle illumination of a surgical field using a variable-angleilluminator in accordance with the teachings of this invention, and asurgical handpiece embodiment of the variable-angle illuminator of thepresent invention for use in ophthalmic surgery. Further, embodiments ofthis invention can be incorporated within a surgical machine or systemfor use in ophthalmic or other surgery. Other uses for a variable-angle,wide-angle illuminator designed in accordance with the teachings of thisinvention will be known to those having skill the art.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

A more complete understanding of the present invention and theadvantages thereof may be acquired by referring to the followingdescription, taken in conjunction with the accompanying drawings, inwhich like reference numbers indicate like features and wherein:

FIG. 1 is a diagrammatic representation of one embodiment of a systemfor variable, wide-angle illumination in accordance with the teachingsof this invention;

FIG. 2 is a diagrammatic representation of an optical fiber/PDLCdiffuser embodiment of the present invention;

FIGS. 3A and 3B are close-up views of the PDLC diffuser of FIG. 2;

FIGS. 4 and 5 are diagrammatic representations of a nested CPC-coneoptical assembly embodiment of the variable-angle illuminator of thepresent invention;

FIG. 6 is a diagram illustrating the use of one embodiment of thevariable-angle illuminator of this invention for ophthalmic surgery;

FIG. 7 is a diagram illustrating an embodiment of an adjusting means 40in accordance with the present invention; and

FIG. 8 is a flowchart illustrating the steps of one embodiment of themethod of this invention.

DETAILED DESCRIPTION OF THE INVENTION

Preferred embodiments of the present invention are illustrated in theFIGURES, like numerals being used to refer to like and correspondingparts of the various drawings.

The various embodiments of the present invention provide for a smallgauge (e.g., 19, 20, or 25 gauge) optical fiber based endo-illuminatordevice for use in surgical procedures, such as invitreo-retinal/posterior segment surgery. Embodiments of this inventioncan comprise a handpiece, such as the Alcon-Grieshaber Revolution-DSP™handpiece sold by Alcon Laboratories, Inc., Fort Worth, Tex., connectedto a small gauge cannula (e.g., 19, 20, or 25 gauge). The innerdimension of the cannula can be used to house one, or a plurality of,optical fibers and/or a diffusive optical element in accordance with theteachings of this invention. Embodiments of the wide-angle illuminatorcan be configured for use in the general field of ophthalmic surgery.However, it is contemplated and it will be realized by those skilled inthe art that the scope of the present invention is not limited toophthalmology, but may be applied generally to other areas of surgerywhere wide-angle and/or variable angle illumination may be required.

An embodiment of the variable-angle, wide-angle illuminator of thisinvention can comprise a light diffusive optical assembly, a stem, and ahandpiece fabricated from biocompatible polymeric materials, such thatthe invasive portion of the wide-angle illuminator is a disposablesurgical item. Embodiments of this invention fabricated frombiocompatible polymeric materials can be integrated into a low cost,articulated handpiece mechanism, such that these embodiments cancomprise an inexpensive disposable illuminator instrument.

The PDLC diffuser embodiments of the present invention rely on theprinciple that liquid crystal molecules are rotated by the presence ofan electric field. With no electric field, the liquid crystal moleculesare randomly oriented and the PDLC layer is highly diffusing. As anelectric field is applied and strengthened, the liquid crystal moleculesbecome increasingly lined up parallel to the electric field. With asufficient electric field strength, the liquid crystal molecules arelined up and the PDLC layer is essentially non-diffusive.

The nested CPC-cone embodiments of the present invention rely on theprinciple that light within a CPC-cone is confined by total internalreflection of rays off of the surface/air interface. Thus, as long asthe male CPC-cone of various embodiments of this invention is surroundedby air, the light transmitted within the CPC-cone will be confinedwithin the male CPC-cone and will funnel down to the end of the CPC-conewhere it will be emitted from the cone distal end with a high angularspread. However, if an air gap between a male and a female CPC-cone iseliminated (e.g., by bringing the male and female CPC-cones intocontact), the light transmitted within the male CPC-cone will no longerbe confined within the male CPC-cone and subject to its funnelingeffect. Some of the light will instead pass into the female CPC-cone,and the light emitted from the distal end of the optical assembly willhave a greatly reduced angular spread.

FIG. 1 is a diagrammatic representation of a surgical system 2comprising a handpiece 10 for delivering a beam of light from a lightsource 12 through cable 14 to a stem (cannula) 16. Cable 14 can be anygauge fiber optic cable as known in the art, but is preferably a cablehaving 19, 20, or 25 gauge fiber. Further, cable 14 can comprise asingle optical fiber or a plurality of optical fibers optically coupledto receive and transmit light from light source 12 to an optical fiber22 within stem 16 through handpiece 10. Handpiece 10 and Stem 16 areconfigured to house optical fiber 22 and a diffusive optical assembly,optically coupled to fiber 22 and operable to receive the light fromlight source 12 and transmit it to illuminate a desired area, such as asurgical site. Embodiments of optical assembly 50 (200) are more clearlyillustrated in FIGS. 2-4. Coupling system 32 can comprise an opticalfiber connector at each end of cable 14 to optically couple light source12 to an optical fiber 22/14 within handpiece 10, as discussed morefully below.

FIG. 2 is a diagrammatic representation of an optical fiber/PDLCdiffuser/optical needle embodiment of the present invention. OpticalAssembly 50 comprises a PDLC diffuser 100 and an optical needle 102. ThePDLC diffuser 100 can consist of a rigid polymer (e.g., plastic) layer150 into which a plurality of liquid crystal droplets 152 have beendispersed, a transparent (e.g, indium tin oxide) proximal electrode 154on the entrance (proximal) face of the polymer layer 150, and atransparent distal electrode 156 on the exit (distal) face of thepolymer layer 150, as shown in FIGS. 3A and 3B. In the absence of anelectric field (FIG. 3A), the liquid crystal molecules within eachliquid crystal droplet 152 are randomly oriented. In this state, theeffective refractive index of each droplet is significantly differentfrom that of the surrounding rigid polymer. Therefore, there is strongreflection and refraction (as well as scattering) of the incoming light160 from light source 12 off of the droplet/polymer interface. Theaggregate macroscopic effect is significant diffusion of the light 160passing through the PDLC diffuser 100. However, when a voltage isapplied across the PDLC diffuser 100 polymer layer (FIG. 3B), the liquidcrystal molecules within each liquid crystal droplet 152 begin to alignthemselves parallel to the electric field. As they do so, the effectiverefractive index of the liquid crystal droplets 152 start approachingthe refractive index of the surrounding polymer layer 150, and theresultant diffusion of the passing light beam 160 decreases. As theapplied voltage increases, the diffusion by the PDLC diffuser 100decreases. When a threshold voltage is reached, the diffusion of thePDLC diffuser 100 is about zero, and the PDLC diffuser 100 isessentially (about) clear.

The diffuse light emitted from the distal face of the PDLC diffuser 100is transmitted into cylindrical needle 102 (or an optical fiber 102 withthe cladding removed). Needle 102 can be a glass needle/optical fiber.When surrounded by air, the needle 102 has an NA of about 1 and iscapable of confining a light beam with a half angle as large as about 90degrees. Therefore, even at the maximum PDLC diffuser 100 diffusion,essentially all of the diffuse light transmitted to the needle 102 canbe transmitted by the needle 102 to its distal end. The needle 102 isenclosed within the stem 16, which can be made of steel. Opticaladhesive 106 can be applied at the distal end of the needle 102/cannula16 assembly to mechanically join the needle 102 to the stem 16, and toensure the needle 102 is surrounded by air gap 104 within stem 16 bypreventing liquid from the eye from getting between the needle 102 andstem 16. To prevent the needle 102 from touching the stem 16 in one ormore places, a small number of glass or plastic spacer balls 170 (usedroutinely in the liquid crystal display industry) can be applied to theneedle 102 surface before inserting the needle 102 into the stem 16. Thespacer balls 170 will keep the needle 102 separated from stem 16, andthe scattered light loss from each spacer ball 170 is anticipated to benegligible.

The electric field applied to the PDLC diffuser 100 can be controlled byany means known to those skilled in the art for controlling the flow ofcurrent within an electronic device. For example, a slide mechanism inthe handpiece 10 can be used as a rheostat type mechanism (switch), orsome other electronic control means can be used, such as a footcontroller, that will be familiar to those having skill in the art. Theelectric field electronic control means can provide a surgeon theability to continuously vary in real time the angular spread of thelight emitted from the illuminator between a narrow field of view (formaximum PDLC diffuser 100 clarity) and a very large field of view (formaximum PDLC diffuser 100 diffusion).

FIGS. 4 and 5 are diagrammatic representations of a nested CPC-coneoptical assembly embodiment of the present invention for controlling theangular spread of light emitted from the illuminator. In thisembodiment, optical assembly 200 comprises a male CPC-cone element 250nested within a female CPC-cone element 252, wherein male CPC-coneelement 250 and female CPC-cone element 252 are in a moveablerelationship to one another. The CPC-cone optical assembly 200 isoptically coupled to the distal end of the optical fiber 22/14 and isdesigned to emit substantially all incoming light out of the planardistal end face 210 of the optical assembly 200 (very little light isemitted out the side surface), emit light over a half angle as large asabout 90 degrees, and emit light with very high efficiency. Lightpassing through the male CPC-cone element 250 remains within theCPC-cone element 250 by total internal reflection at the polymer/airinterface on the side wall of the male CPC-cone element 250. Thetapering male CPC-cone element 250 causes the light to funnel down andincrease its angular spread until the light is emitted from the distalend face 210 over a wide angle.

The wide angular spread of emitted light from the male CPC-cone element250 depends on air surrounding the CPC-cone element 250 (i.e., on acone-to-air interface). Therefore, if there is no air gap 254 betweenthe male CPC-cone element 250 and the female CPC-cone element 252, thewide angular spreading of light by the male CPC-cone element 250 cannotoccur. One way to eliminate the air gap 254 is illustrated in FIGS. 4and 5. A male CPC-cone element 250 is nested within a slightly truncatedfemale CPC-cone element 252, with a variable-width air gap 254 betweenthem. In FIG. 4, the female CPC-cone element 252 is in an extendedposition, causing an air gap 254 to exist between the two CPC-coneelements 250 and 252, and resulting in an angularly broad beam of light270 emitted from the distal end face 210 of the male CPC-cone element250. In FIG. 5, the female CPC-cone element 252 is shown in a retractedposition in contact with male CPC-cone element 250. The air gap 254between the CPC-cone elements does not exist when female CPC-coneelement 252 is fully retracted. In this case, the two CPC-cone elements250 and 252 behave optically as if there is no joint between them, andthey are effectively a single untapered cylindrical optical element. Theresultant beam of emitted light 272 is angularly narrow—about the sameangular width as would be emitted from an optical fiber 22/14 withoutthe CPC-cone optical assembly 200.

When the rays of a light beam transmitted by the optical fiber 14/22 andCPC-cone element 250 reflect off of the cone/air interface within themale CPC-cone element 250, an evanescent wave is generated that extendsa very short distance (e.g., microns) beyond the CPC-cone surface/airinterface and into the surrounding air medium. As long as the surface ofthe female CPC-cone element 252 remains outside of the evanescent waveregion, total internal reflection will occur within the male CPC-coneelement 250. If, however, the female CPC-cone element 252 is closeenough that its surface is encroaching within the region of theevanescent wave, some of the light ray energy will cross into the femaleCPC-cone element 252 as a traveling wave. As the air gap 254 between theCPC-cone elements decreases, the amount of light passing into the femaleCPC-cone element 252 increases. When the air gap 254 is eliminated,essentially 100% of the transmitted light will pass into the femaleCPC-cone element 252 from the male CPC-cone element 250. Therefore,moving the female CPC-cone element 252 longitudinally only a very shortdistance along the optical axis will cause the emitted light to switchfrom a maximum angular spread to a minimum angular spread. In theory itis possible to adjust the air gap 254 to cause an intermediate beamspread somewhere between the two extremes, but in practice this may beextremely difficult to achieve as the sensitivity of the beam spread tothe air gap size in the transition region is high.

In one embodiment, the female CPC-cone element 252 can be operablycoupled to stem 16 that covers the entire optical fiber 22(14)/CPC-coneoptical assembly 200. In such an embodiment, at least two differentoptions can be employed: (1) the stem 16 and female CPC-cone element 252can be rigidly attached to the handpiece 10 (e.g., to one another) andthe optical fiber 22(14)/male CPC-cone element 250 can be operable tomove longitudinally along the optical axis, or (2) the optical fiber22(14) and male CPC-cone element 250 can be rigidly attached to thehandpiece 10 and the stem 16 and female CPC-cone element 252 can beoperable to move longitudinally along the optical axis. In either case,the switching beam states (longitudinal movement of the moveablecomponents) can be controlled by a slide or toggle switch mechanism inor on the handpiece 10 in a manner that will be known to those havingaverage skill in the art.

When used in an embodiment, optical fiber 22 can be optically coupled tofiber optic cable 14. In some embodiments, however, fiber optic cable 14can extend through the handpiece 10 and is optically coupled directly tothe optical assembly 50 (200) comprising PDLC diffuser 100 or CPC-coneelements 250/252. For these embodiments, a separate optical fiber 22 isnot used. When implemented within handpiece 10, optical fiber 22 is of agauge compatible with the gauge of fiber optic cable 14, such that itcan receive and transmit light from fiber optic cable 14. Handpiece 10can be any surgical handpiece as known in the art, such as theRevolution-DSP™ handpiece sold by Alcon Laboratories, Inc. of FortWorth, Tex. Light source 12 can be a xenon light source, a halogen lightsource, or any other light source capable of delivering light through afiber optic cable. Stem 16 can be a small gauge cannula, preferably onthe order of 19, 20, or 25 gauge, as known to those having skill in theart. Stem 16 can be stainless steel or a suitable biocompatible polymer(e.g., PEEK, polyimide, etc.) as known to those having skill in the art.

The fiber optic cable 14 or optical fiber 22, CPC-cone elements 250/252and/or stem 16 (in such combinations as described above) can be operablycoupled to the handpiece 10, for example, via an adjusting means 40, asshown in FIG. 7. Adjusting means 40 can comprise, for example, apush/pull mechanism as known to those having skill in the art, such as apiston to which the moveable components are operably coupled. The pistoncan be controlled via adjusting means 40, which can be a manualmechanical device for moving the piston or an electro-mechanicalactuator (switch) for controlling an electro-mechanical means for movingthe piston, as will be known to those having skill in the art. Lightsource 12 can be optically coupled to handpiece 10 (e.g., to fiber 22)using, for example, standard SMA (Scale Manufacturers Association)optical fiber connectors at the ends of fiber optic cable 14. Thisallows for the efficient coupling of light from the light source 12through fiber optic cable 14/optical fiber 22 and the handpiece 10 andfinally emanating from optical assembly 50 (200) at the distal end ofthe stem 16. Light source 12 may comprise filters, as known to thoseskilled in the art, to reduce the damaging thermal effects of absorbedinfrared radiation originating at the light source. The light source 12filter(s) can be used to selectively illuminate a surgical field withdifferent colors of light, such as to excite a surgical dye. Fiber(s) 22(and/or 14, depending on the embodiment) is/are terminated by opticallycoupling to the optical assembly 50 (200) comprising PDLC diffuser100/needle 102 or CPC-cone elements 250/252.

FIG. 6 illustrates the use of one embodiment of the variable-angle,wide-angle illuminator of this invention in an ophthalmic surgery. Inoperation, handpiece 10 delivers a beam of light through stem 16 (viafiber optic cable 14 and or optical fiber 22) and through opticalassembly 50 (200) to illuminate a retina 28 of an eye 30. The collimatedlight delivered through handpiece 10 to the optical assembly 50 (200) isgenerated by light source 12 and delivered to illuminate the retina 28by means of fiber optic cable 14 and coupling system 32. Opticalassembly 50 (200) is operable to spread the light beam delivered fromlight source 12 over as large an area of the retina as, for example, amicroscopic wide-angle objective lens permits a surgeon to see.

In one embodiment of the variable-angle, wide-angle illuminator of thepresent invention, a simple mechanical locking mechanism, as known tothose skilled in the art, can permit the illumination angle to be fixed,until released and/or readjusted by the user via the adjusting means 40.

An advantage of the embodiments of the variable-angle, wide-angleilluminator of this invention, is that an operator can vary the angle ofillumination of emitted light from the distal end of the illuminator inreal time to optimize viewing conditions within the surgical field. Theangular spread of the emitted light can thus be controlled as desired bythe operator

FIG. 7 provides another view of a wide-angle illuminator according tothe teachings of this invention showing more clearly an embodiment ofadjusting means 40. In this embodiment, adjusting means 40 comprises aslide button, as known to those skilled in the art. Activation ofadjusting means 40 on handpiece 10 by, for example, a gentle andreversible sliding action, can cause a change in the diffusion rate ofPDLC diffuser 100 or cause a change in the relative positions betweenmale CPC cone element 250 and female CPC cone element 252, in the mannerdescribed above. Adjusting means 40 can comprise, for example, apush/pull mechanism as known to those having skill in the art, such as apiston to which the moveable components are operably coupled. The pistoncan be controlled via adjusting means 40, which can be a manualmechanical device for moving the piston or an electro-mechanicalactuator (switch) for controlling an electro-mechanical means for movingthe piston, as will be known to those having skill in the art. Adjustingmeans 40 can also comprise, in other embodiments, a simple on/offswitch, as will be known to those having skill in the art, for changingthe diffusion of PDLC diffuser 100 from a maximum, to a minimum (andvice-versa) or can control a rheostat type mechanism for continuouslyvarying the diffusion rate of PDLC diffuser 100.

FIG. 8 is a logic flow diagram illustrating a method operable to providevariable, wide-angle illumination in accordance with the teachings ofthis invention. Operations 800 begin with the generation of a light beamin step 802. This light beam may be generated from a light source suchas light source 12 as described with reference to the prior Figures. Instep 804 an optical cable receives the light beam. The light beamreceived by the optical cable is then transmitted to an optical fiber instep 806. In step 808 an optical assembly is coupled to the distal endof the optical fiber where the optical assembly receives the light beam.In step 810, the optical assembly is directed to illuminate a selectedarea in step 810. The optical assembly may spread the light beamdelivered from the light source over a large area. For example, whenused in ophthalmic surgery, this light beam may be delivered to the areaof the retina to allow a microscopic wide-angle objective lens thatpermits a surgeon to see this surgical area. The angular spread of theemitted light delivered by the optical assembly may be controlled asdesired in order to optimize viewing conditions within the surgicalfield. The optical assembly can comprise any of the embodimentsdescribed herein in accordance with the present invention.

Although the present invention has been described in detail herein withreference to the illustrated embodiments, it should be understood thatthe description is by way of example only and is not to be construed ina limiting sense. It is to be further understood, therefore, thatnumerous changes in the details of the embodiments of this invention andadditional embodiments of this invention will be apparent to, and may bemade by, persons of ordinary skill in the art having reference to thisdescription. It is contemplated that all such changes and additionalembodiments are within the spirit and true scope of this invention asclaimed below. Thus, while the present invention has been described inparticular reference to the general area of ophthalmic surgery, theteachings contained herein apply equally wherever it is desirous toprovide wide-angle and variable illumination of a surgical site.

What is claimed is:
 1. A variable-angle illumination surgical systemcomprising: a light source for providing a light beam; an optical cable,optically coupled to the light source for receiving and transmitting thelight beam; a handpiece, operably coupled to the optical cable; anoptical fiber, operably coupled to the handpiece, wherein the opticalfiber is optically coupled to the optical cable to receive and transmitthe light beam; an optical assembly; and a cannula, wherein the cannulais operably coupled to the handpiece and optical assembly for housingand directing the optical assembly to illuminate an area; wherein theoptical assembly is optically coupled to a distal end of the opticalfiber for receiving the light beam and providing the light beam toilluminate the area; wherein the optical assembly comprises a malecompound parabolic concentrator (CPC) cone element nested within afemale CPC-cone element, wherein the female CPC-cone element translatesover the male CPC-cone element to vary an air gap formed therebetweenand thereby vary the off-axis, angular spread of light emitted out of adistal end of the cannula.
 2. The variable-angle illumination surgicalsystem of claim 1, wherein the area comprises a surgical site.
 3. Thevariable-angle illumination surgical system of claim 1, wherein theoptical fiber comprises an endo-illuminator optical fiber having a 0.50NA.
 4. The variable-angle illumination surgical system of claim 1,wherein the angular spread of the light emitted by the optical assemblyis determined by the proximity of the female CPC-cone element to themale CPC-cone element.
 5. The variable-angle illumination surgicalsystem of claim 1, wherein the cannula, optical assembly and thehandpiece are fabricated from biocompatible materials.
 6. A method forwide-angle illumination of a surgical field using a variable-angleilluminator comprising: generating a light beam; receiving the lightbeam with an optical cable, wherein a handpiece is operably coupled tothe optical cable; transmitting the light beam from the optical cable toan optical fiber, wherein the handpiece is operably coupled to theoptical fiber; optically coupling an optical assembly to a distal end ofthe optical fiber, wherein the optical assembly receives the light beamand comprises a male compound parabolic concentrator (CPC) cone elementnested within a female CPC-cone element; directing the optical assemblyto illuminate a selected area; translating the female CPC-cone elementover the male CPC-cone element to vary an air gap formed between themale and female CPC-cones and thereby control the degree of diffusion ofthe light beam emitted out of the optical assembly.
 7. The method ofclaim 6, wherein the directing step further comprises illuminating asurgical site.